gistfile1.txt

trait Integer {}
impl Integer for int {}

trait Float          { static fn NaN() -> Self;           }
impl Float for float { static fn NaN() -> float { 0./0. } }

trait NumStrHelper {
    static fn has_special_values() -> bool;
    static fn NaN() -> Option<Self>;
    fn is_NaN(&self) -> bool;

    // ...
}

impl <T: Integer> NumStrHelper for T {
    static fn has_special_values() -> bool { false }
    static fn NaN() -> Option<T> { None }
    fn is_NaN(&self) -> bool { false }

    // ...
}
impl <U: Float Eq> NumStrHelper for U {
    static fn has_special_values() -> bool { true }
    static fn NaN() -> Option<U> { Some(Float::NaN()) }
    fn is_NaN(&self) -> bool { *self != *self  }

    // ...
}

fn main() {

}